A Method provides information about, and access to, a single method
on a class or interface. The reflected method may be a class method
or an instance method (including an abstract method).

A Method permits widening conversions to occur when matching the
actual parameters to invoke with the underlying method's formal
parameters, but it throws an IllegalArgumentException if a
narrowing conversion would occur.

Method Detail

setAccessible

Set the accessible flag for this reflected object to
the indicated boolean value. A value of true indicates that
the reflected object should suppress checks for Java language access
control when it is used. A value of false indicates that
the reflected object should enforce checks for Java language access
control when it is used, with the variation noted in the class description.

This method may be used by a caller in class C to enable
access to a member of declaring classD if any of the following hold:

C and D are in the same module.

The member is public and D is public in
a package that the module containing Dexports to at least the module
containing C.

The member is protectedstatic, D is
public in a package that the module containing D
exports to at least the module containing C, and C
is a subclass of D.

D is in a package that the module containing Dopens to at least the module
containing C.
All packages in unnamed and open modules are open to all modules and
so this method always succeeds when D is in an unnamed or
open module.

This method cannot be used to enable access to private members,
members with default (package) access, protected instance members, or
protected constructors when the declaring class is in a different module
to the caller and the package containing the declaring class is not open
to the caller's module.

If there is a security manager, its
checkPermission method is first called with a
ReflectPermission("suppressAccessChecks") permission.

getTypeParameters

Returns an array of TypeVariable objects that represent the
type variables declared by the generic declaration represented by this
GenericDeclaration object, in declaration order. Returns an
array of length 0 if the underlying generic declaration declares no type
variables.

getParameterTypes

Returns an array of Class objects that represent the formal
parameter types, in declaration order, of the executable
represented by this object. Returns an array of length
0 if the underlying executable takes no parameters.

getGenericParameterTypes

Returns an array of Type objects that represent the formal
parameter types, in declaration order, of the executable represented by
this object. Returns an array of length 0 if the
underlying executable takes no parameters.

If a formal parameter type is a parameterized type,
the Type object returned for it must accurately reflect
the actual type parameters used in the source code.

If a formal parameter type is a type variable or a parameterized
type, it is created. Otherwise, it is resolved.

getExceptionTypes

Returns an array of Class objects that represent the
types of exceptions declared to be thrown by the underlying
executable represented by this object. Returns an array of
length 0 if the executable declares no exceptions in its
throws clause.

getGenericExceptionTypes

Returns an array of Type objects that represent the
exceptions declared to be thrown by this executable object.
Returns an array of length 0 if the underlying executable declares
no exceptions in its throws clause.

If an exception type is a type variable or a parameterized
type, it is created. Otherwise, it is resolved.

equals

Compares this Method against the specified object. Returns
true if the objects are the same. Two Methods are the same if
they were declared by the same class and have the same name
and formal parameter types and return type.

toString

Returns a string describing this Method. The string is
formatted as the method access modifiers, if any, followed by
the method return type, followed by a space, followed by the
class declaring the method, followed by a period, followed by
the method name, followed by a parenthesized, comma-separated
list of the method's formal parameter types. If the method
throws checked exceptions, the parameter list is followed by a
space, followed by the word "throws" followed by a
comma-separated list of the thrown exception types.
For example:

public boolean java.lang.Object.equals(java.lang.Object)

The access modifiers are placed in canonical order as
specified by "The Java Language Specification". This is
public, protected or private first,
and then other modifiers in the following order:
abstract, default, static, final,
synchronized, native, strictfp.

toGenericString

Returns a string describing this Method, including
type parameters. The string is formatted as the method access
modifiers, if any, followed by an angle-bracketed
comma-separated list of the method's type parameters, if any,
followed by the method's generic return type, followed by a
space, followed by the class declaring the method, followed by
a period, followed by the method name, followed by a
parenthesized, comma-separated list of the method's generic
formal parameter types.
If this method was declared to take a variable number of
arguments, instead of denoting the last parameter as
"Type[]", it is denoted as
"Type...".
A space is used to separate access modifiers from one another
and from the type parameters or return type. If there are no
type parameters, the type parameter list is elided; if the type
parameter list is present, a space separates the list from the
class name. If the method is declared to throw exceptions, the
parameter list is followed by a space, followed by the word
"throws" followed by a comma-separated list of the generic
thrown exception types.

The access modifiers are placed in canonical order as
specified by "The Java Language Specification". This is
public, protected or private first,
and then other modifiers in the following order:
abstract, default, static, final,
synchronized, native, strictfp.

invoke

Invokes the underlying method represented by this Method
object, on the specified object with the specified parameters.
Individual parameters are automatically unwrapped to match
primitive formal parameters, and both primitive and reference
parameters are subject to method invocation conversions as
necessary.

If the underlying method is static, then the specified obj
argument is ignored. It may be null.

If the number of formal parameters required by the underlying method is
0, the supplied args array may be of length 0 or null.

If the underlying method is an instance method, it is invoked
using dynamic method lookup as documented in The Java Language
Specification, Second Edition, section 15.12.4.4; in particular,
overriding based on the runtime type of the target object will occur.

If the underlying method is static, the class that declared
the method is initialized if it has not already been initialized.

If the method completes normally, the value it returns is
returned to the caller of invoke; if the value has a primitive
type, it is first appropriately wrapped in an object. However,
if the value has the type of an array of a primitive type, the
elements of the array are not wrapped in objects; in
other words, an array of primitive type is returned. If the
underlying method return type is void, the invocation returns
null.

Parameters:

obj - the object the underlying method is invoked from

args - the arguments used for the method call

Returns:

the result of dispatching the method represented by
this object on obj with parameters
args

Throws:

IllegalAccessException - if this Method object
is enforcing Java language access control and the underlying
method is inaccessible.

IllegalArgumentException - if the method is an
instance method and the specified object argument
is not an instance of the class or interface
declaring the underlying method (or of a subclass
or implementor thereof); if the number of actual
and formal parameters differ; if an unwrapping
conversion for primitive arguments fails; or if,
after possible unwrapping, a parameter value
cannot be converted to the corresponding formal
parameter type by a method invocation conversion.

true if and only if this executable is a synthetic
construct as defined by
The Java™ Language Specification.

Since:

1.5

See The Java™ Language Specification:

13.1 The Form of a Binary

isDefault

public boolean isDefault​()

Returns true if this method is a default
method; returns false otherwise.
A default method is a public non-abstract instance method, that
is, a non-static method with a body, declared in an interface
type.

Returns:

true if and only if this method is a default
method as defined by the Java Language Specification.

Since:

1.8

getDefaultValue

Returns the default value for the annotation member represented by
this Method instance. If the member is of a primitive type,
an instance of the corresponding wrapper type is returned. Returns
null if no default is associated with the member, or if the method
instance does not represent a declared member of an annotation type.

Returns:

the default value for the annotation member represented
by this Method instance.

getDeclaredAnnotations

Returns annotations that are directly present on this element.
This method ignores inherited annotations.
If there are no annotations directly present on this element,
the return value is an array of length 0.
The caller of this method is free to modify the returned array; it will
have no effect on the arrays returned to other callers.

getParameterAnnotations

Returns an array of arrays of Annotations that
represent the annotations on the formal parameters, in
declaration order, of the Executable represented by
this object. Synthetic and mandated parameters (see
explanation below), such as the outer "this" parameter to an
inner class constructor will be represented in the returned
array. If the executable has no parameters (meaning no formal,
no synthetic, and no mandated parameters), a zero-length array
will be returned. If the Executable has one or more
parameters, a nested array of length zero is returned for each
parameter with no annotations. The annotation objects contained
in the returned arrays are serializable. The caller of this
method is free to modify the returned arrays; it will have no
effect on the arrays returned to other callers.
A compiler may add extra parameters that are implicitly
declared in source ("mandated"), as well as parameters that
are neither implicitly nor explicitly declared in source
("synthetic") to the parameter list for a method. See Parameter for more information.

getAnnotatedReturnType

Returns an AnnotatedType object that represents the use of a type to
specify the return type of the method/constructor represented by this
Executable.
If this Executable object represents a constructor, the
AnnotatedType object represents the type of the constructed object.
If this Executable object represents a method, the
AnnotatedType object represents the use of a type to specify the return
type of the method.